Spider web at Montana de Oro; photo by Sean Chamberlin
Is Gaia Here?
The startling and pervasive expansion of life on Earth begs several questions concerning the nature of evolution and the processes which feed it. In a strict Darwinian sense, new life arose as competitive pressures made other life unsuccessful. Species at a disadvantage came to an end. On the other end of the spectrum, the cooperation between cells at a very early stage -- the process of symbiogenesis -- casts a different view of the development of life on the planet.
Whether life arose and took command of planetary processes for its own good, as proposed by Lovelock in his Gaia theory; whether life arose as the sum of populations of individual genomes with an expressed fitness or ability to survive under a given set of environmental conditions, as popularly expressed by evolutionists and molecular biologists; or whether some laws of non-equilibrium thermodynamics pulsate at the quantum level of life such that symbiotic organisms, communities of organisms, and entire ecosystems had to arise to satisfy these pulses, as suggested by some physicists and myself, are questions that will continue to drive our science. The importance of looking backwards into the fossil record, and indeed, into space, cannot be overstated. The evolution of life and biogeochemical processes on this planet will be most easily understood by gaining some sense of what has happened in the past, be it on our planet or in the far reaches of interstellar space.
In this quest, we must also look ahead. We must gauge the effects of our own mechanization and evolution on the globe. We must scrutinize the smallest impacts and synthesize their individual fluxes into a global model that gives us the best picture of what might happen to our planet. We have to give it our best shot. As evidenced by the rapid demise of many marine organisms 245 million years ago and the dinosaurs 65 million years ago, the Universe waits for no one.
What does this have to do with Gaia? Only that it is prudent to keep our minds open to all possibilities. Life's extraordinary "gift" of oxygen 2 billion years ago, and its maintenance of that "gift" for another 2 billion, exemplify the power that life -- microbial life -- holds over the planet. We would be wise not to dismiss the possibility that microorganisms hold the purse strings of other equally powerful planetary processes. If the foundations of Gaia lie in the microbial world, and a good case could be made for this premise, then man's reign here is not because of his own advanced evolutionary state; rather, man is here by permission.
Considering that every cell in our body contains a mitochondrion, which originated as a bacterial cell, and considering that our own bodies contain as many as ten thousand billion bacterial cells -- nearly ten percent of our body weight -- we might be wise to reflect on who is ruling whom!
Be that as it may, we will discuss at a later date the possible mechanisms and evidence for them that would support the idea of an interconnected, Gaian planet. In the meantime, I will leave you with these few paragraphs from Margulis and Sagan, which sums up much of which we have just learned.
It is an illuminating peculiarity of the microcosm that explosive geological events in the past have never led to the total destruction of the biosphere. Indeed, like an artist whose misery catalyzes beautiful works of art, extensive catastrophe seems to have immediately preceded major evolutionary innovations.
Life on Earth answers threats, injuries, and losses with innovations, growth, and reproduction. The disastrous loss of needed hydrogen from the gravitational field of the earth led to one of the greatest evolutionary innovations of all time: the use of water (H2O) in photosynthesis. But it has also led to a tremendous pollution crisis, the accumulation of oxygen gas, which was originally toxic to the vast majority of organisms living on the planet. Nonetheless, the oxygen crisis 1,000 million years ago promoted the evolution of respiring bacteria which used oxygen to derive biochemical energy more efficiently than ever before. These bacteria were symbiotic and merged with other bacteria to form eukaryotic cells -- which, becoming multicellular, evolved into fungi, plants, and animals. The most severe mass extinctions the world has ever known, at the Permo-Triassic boundary 245 million years ago, were rapidly followed by the rise of mammals, with their sharp eyes and large receptive brains. The Cretaceous catastrophe, including the disappearance of dinosaurs 66 million years ago, cleared the way for the development of the first primates, whose intricate eye-hand coordination led to technology. World War II ushered in radar, nuclear weapons, and the electronic age. And the holocaust of Hiroshima and Nagasaki over forty years ago decimated Japanese industry and culture, unwittingly clearing the way for a new beginning in the form of a rising red sun of the Japanese information empire.
With each crisis the biosphere seems to take one step backwards and two steps forward -- the two steps forward being an evolutionary solution that surmounts the boundaries of the original problem. Not only meeting but going beyond challenges confirms that the biosphere is extremely resilient, that it recovers from tremors with renewed vigor. Nuclear conflagration in the northern hemisphere would kill hundreds of millions of human beings. But it would not be the end of life on Earth, and, as heartless as it sounds, a human Armageddon might prepare the biosphere for less self-centered forms of life. As different from us as we are from dinosaurs, such future beings may have evolved through matter, life, and consciousness to a new superordinate stage of organization, and in doing so, consider human beings as impressive as we do iguanas.
While boldly stated and even startling, these paragraphs in their book at least help us to step back from our human-centric view of life, and help us to consider the enormity of life forces of which we are a part. Much as ancient men had to reconcile the fact that the Earth was not the center of the Universe, so too might modern man have to realize that he is not the dominant player in the circle of Life on this planet.
Question: If Gaia did begin to operate during the evolution of the Earth, when might it have started?